Due to aging and external stresses such as temperature, humidity, and UV rays, the skin gradually produces wrinkles and other unfavorable conditions such as rough skin. Previous studies have revealed that hypofunction of fibroblasts in the dermis of the skin and reduction or degradation of the matrix fiber is likely to contribute to the production of wrinkles, etc. To ameliorate such conditions, a variety of means have heretofore been proposed. For example, mention may be given of uses of a loquat (i.e., Japanese medlar) extract (Patent Document 1), oxidized coenzyme A (Patent Document 2), and Agaricus mushrooms (Patent Documents 3 and 4). However, those are still not fully satisfactory in terms of wrinkle inhibitory effect and safety.
Meanwhile, it has been reported that a culture supernatant of a lactic acid bacterium; i.e., a culture obtained through inoculating lactic acid bacteria into a medium containing milk as a primarily ingredient, exhibits desirable effects as a skincare preparation for external use. For example, a culture supernatant of a lactic acid bacterium (hereinafter may be referred to as “lactic acid bacterium culture supernatant”) has been reported to have a moisturizing effect (Non-Patent Document 1), an antioxidative effect (Non-Patent Document 2), a protective effect against light (Non-Patent Document 3), and a bacterial flora regulating action on the skin and a skin pH control action (Non-Patent Document 4).
Also, in recent years, extensive studies have been conducted on polysaccharides that are produced outside the cells through metabolism of lactic acid bacteria and are contained in a lactic acid bacterium culture supernatant, and thus, many techniques have been reported in relation to external skincare preparations utilizing, as an active ingredient, extracellular polysaccharides produced by various lactic acid bacteria.
Included among such techniques are the use of phosphorylated polysaccharides produced by Streptococcus lactis, Lactococcus lactis, or a similar microorganism as a moisturizing agent or a whitening agent (Patent Documents 5 and 6); and the use of polysaccharides produced by a lactic acid bacterium which belongs to the genus Lactobacillus as an antiinflammatory agent (Patent Document 7).
These lactic acid bacterium culture supernatants (or extracellular polysaccharides produced by lactic acid bacteria), however, have all been used to produce external skincare preparations whose expected efficacy is moisturizing effect or antioxidative effect, and hitherto, no lactic acid bacterium culture supernatant has been found to be particularly effective in preventing wrinkle formation.    [Patent Document 1] JP-B-1993-17206    [Patent Document 2] JP-A-1996-175961    [Patent Document 3] JP-A-1999-228438    [Patent Document 4] JP-A-1999-228439    [Patent Document 5] JP-A-1998-251140    [Patent Document 6] JP-A-1997-249524    [Patent Document 7] JP-A-1995-70209    [Non-Patent Document 1] Journal of Japanese Cosmetic Science Society, 6(4), p 238, 1982    [Non-Patent Document 2] Journal of Japanese Cosmetic Science Society, Proceedings of the 7th Academic Meeting, 59, 1982    [Non-Patent Document 3] Journal of Japanese Cosmetic Science Society, Proceedings of the 8th Academic Meeting, 210, 1983    [Non-Patent Document 4] Journal of Japanese Cosmetic Science Society, Proceedings of the 9th Academic Meeting, 132, 1984